1. Field of the Invention
The present invention relates to a mixing apparatus for manufacturing materials and products by mixture and reaction of fluids, a dispersion manufacturing apparatus and a dispersion manufacturing method in the chemical and pharmaceutical industries.
2. Description of the Related Art
As an aqueous dispersion material containing functional material, there have been hitherto known functional materials composed of agricultural chemicals such as herbicide and insecticide, medicine such as anticancer drug, antiallergic agent and antiphlogistine, and colorant such as ink with colorant and toner. A digital printing technique has made significant progress in recent years. A typical digital printing technique is electrophotography and ink jet technique and has enhanced its presence as an image forming technique in office and home in late years.
In the digital printing technique, the ink jet technique as a direct recording method features compactness and low consumption power. The ink jet technique has been increasingly directed toward higher image quality according to the miniaturization of a nozzle.
There has been known a method as one example of the ink jet technique in which ink supplied from an ink tank is heated by a heater in a nozzle to perform evaporation foam, ejecting ink to form images on recording medium. As another example a method has been known in which a piezoelectric element is vibrated to eject ink from a nozzle.
The ink used in the methods sometimes causes blur at the time of superposing colors because aqueous solution of dye is typically used and phenomenon referred to as feathering in the direction of fibers at a recording place on the recording medium. U.S. Pat. No. 5,085,698 discloses that pigment dispersion ink is used to improve the above problems. However, the pigment dispersion ink is probably inferior to dye ink. For example, light scattering and light reflection are caused by pigment particles, so that images formed by the pigment ink generally tends to be lower in coloring than those by dye ink. Coarse pigment particles cause clogging of the nozzle of an ink jet head. An attempt has been made to fine pigment particles as one of the methods of improving the problems with the pigment ink. The pigment made finer in size to 100 nm or less is less affected by light scattering and increases in specific surface area, so that improvement in coloring is expected.
There has been known a method of dispersing pigments using a microjet reactor to obtain excellent pigment dispersions. For example, Japanese Patent Application Laid-Open No. 2002-155221 discloses a method as a method of producing pigment dispersion ink in which solution in which coarse pigment is dissolved into solvent and a precipitant medium are sprayed from a nozzle to collide with each other in a reactor chamber surrounded by a housing, obtaining pigment suspension. Solution ejected from the nozzle may cause pigments formed by precipitation in the reactor chamber to stick to the inner wall of the chamber to cause precipitation and deposition on the inner wall of the chamber or peeling of the deposition, so that it is not always easy to stably obtain pigment suspension for a long time.
Japanese Patent Application Laid-Open No. 2002-336667 discloses a method of mixing two different liquids at a high speed to form solid deposit. In this method, two different liquids are supplied to an orifice and then caused to pass through a divergent shielding portion at a high speed to produce the solid deposit in a jet collision mixing room. The use of such a micro mixer enables producing minute particles with a narrower particle-size distribution as compared with the case where a conventional batch method using a large capacity tank is used as a place of mixing and reaction.
However, a mixing efficiency needs to be further improved to reduce and uniform particle diameter, for this reason, a nozzle diameter requires to be reduced to decrease the absolute amount of liquid. Furthermore, a plurality of micro mixers mentioned above needs to be arranged to improve productivity. This requires wider space for the micro mixers.
The present invention has been made in view of the problems in the above related art and has for its purpose to provide a fluid mixing apparatus and a dispersion manufacturing apparatus which are small in dispersion of products, stable in production and adapted to space saving and mass production of products.